From df159349172f69c7217612cffef06207b8d59ffa Mon Sep 17 00:00:00 2001
From: Simon Cozens <simon@simon-cozens.org>
Date: Wed, 17 Feb 2021 14:34:35 +0000
Subject: [PATCH] Allow choosing CoreText shaper

---
 Lib/fontgoggles/font/baseFont.py  |  5 +++--
 Lib/fontgoggles/mac/mainWindow.py | 18 +++++++++++++++++-
 Lib/fontgoggles/misc/hbShape.py   |  4 ++--
 Lib/fontgoggles/project.py        |  1 +
 4 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/Lib/fontgoggles/font/baseFont.py b/Lib/fontgoggles/font/baseFont.py
index 198a06df..f0caf2a1 100644
--- a/Lib/fontgoggles/font/baseFont.py
+++ b/Lib/fontgoggles/font/baseFont.py
@@ -131,10 +131,11 @@ def getGlyphRunFromTextInfo(self, textInfo, colorPalettesIndex=0, **kwargs):
 
     def getGlyphRun(self, text, *, features=None, varLocation=None,
                     direction=None, language=None, script=None,
-                    colorLayers=False):
+                    colorLayers=False, shaper="ot"):
         self.setVarLocation(varLocation)
         glyphInfo = self.shaper.shape(text, features=features, varLocation=varLocation,
-                                      direction=direction, language=language, script=script)
+                                      direction=direction, language=language, script=script,
+                                      shaper=shaper)
         glyphNames = (gi.name for gi in glyphInfo)
         for glyph, glyphDrawing in zip(glyphInfo, self.getGlyphDrawings(glyphNames, colorLayers)):
             glyph.glyphDrawing = glyphDrawing
diff --git a/Lib/fontgoggles/mac/mainWindow.py b/Lib/fontgoggles/mac/mainWindow.py
index 2e01917b..efcb4b6b 100644
--- a/Lib/fontgoggles/mac/mainWindow.py
+++ b/Lib/fontgoggles/mac/mainWindow.py
@@ -59,6 +59,8 @@
 feaVarTabLabels = ["Features", "Variations", "Options"]
 feaVarTabValues = [v.lower() for v in feaVarTabLabels]
 
+shaperOptions = ["HarfBuzz", "CoreText"]
+shaperValues = ["ot", "coretext"]
 
 class FGMainWindowController(AppKit.NSWindowController, metaclass=ClassNameIncrementer):
 
@@ -375,6 +377,14 @@ def setupGeneralSettingsGroup(self):
         group.languagesPopup = self.languagesPopup
         y += 50
 
+        self.shaperPopup = LabeledView(
+            (10, y, -10, 40), "Shaper:",
+            PopUpButton, shaperOptions,
+            callback=self.shaperChangedCallback,
+        )
+        group.shaperPopup = self.shaperPopup
+        y += 50
+
         group.setPosSize((0, 0, 0, y))
         self.setLanguagesFromScript()
         return group
@@ -640,7 +650,8 @@ def setFontItemText(self, fontItemInfo, fontItem):
             glyphs = font.getGlyphRunFromTextInfo(self.textInfo,
                                                   features=self.project.textSettings.features,
                                                   varLocation=self.project.textSettings.varLocation,
-                                                  colorLayers=self.project.textSettings.enableColor)
+                                                  colorLayers=self.project.textSettings.enableColor,
+                                                  shaper=self.project.textSettings.shaper)
         stderr = stderr.getvalue()
         if stderr:
             fontItem.writeCompileOutput(stderr)
@@ -934,6 +945,11 @@ def languagesPopupCallback(self, sender):
         self.project.textSettings.language = tag
         self.textEntryChangedCallback(self.textEntry, updateCharacterList=False)
 
+    @objc.python_method
+    def shaperChangedCallback(self, sender):
+        self.project.textSettings.shaper = shaperValues[sender.get()]
+        self.textEntryChangedCallback(self.textEntry, updateCharacterList=True)
+
     @objc.python_method
     def featuresChanged(self, sender):
         self.project.textSettings.features = self.featuresGroup.get()
diff --git a/Lib/fontgoggles/misc/hbShape.py b/Lib/fontgoggles/misc/hbShape.py
index 419235eb..e37c0426 100644
--- a/Lib/fontgoggles/misc/hbShape.py
+++ b/Lib/fontgoggles/misc/hbShape.py
@@ -154,7 +154,7 @@ def getGlyphID(self, glyphName, default=0):
             return default
 
     def shape(self, text, *, features=None, varLocation=None,
-              direction=None, language=None, script=None):
+              direction=None, language=None, script=None, shaper="ot"):
         if features is None:
             features = {}
         if varLocation is None:
@@ -178,7 +178,7 @@ def shape(self, text, *, features=None, varLocation=None,
         if script is not None:
             buf.set_script_from_ot_tag(script)
 
-        hb.shape(self.font, buf, features)
+        hb.shape(self.font, buf, features, shapers=[shaper])
 
         glyphOrder = self.glyphOrder
         infos = []
diff --git a/Lib/fontgoggles/project.py b/Lib/fontgoggles/project.py
index 1e0ca8de..e3e6724d 100644
--- a/Lib/fontgoggles/project.py
+++ b/Lib/fontgoggles/project.py
@@ -208,6 +208,7 @@ class TextSettings:
     relativeVBaseline: float = 0.5
     relativeMargin: float = 0.1
     enableColor: bool = True
+    shaper: str = "ot"
 
 
 @dataclass